Associações no uso do hábitat por cinco espécies de lagartos amazônicos

Abstract

The present study investigated the effects of environmental factors on the distribution of the five commonest lizard species in two areas with distinct ranges of environmental variation. The surveys were done at the Viruá National Park and at the Maracá Ecological Station, Roraima, Brazil, from September 2006 to March 2007 (dry season), in 30 plots at each locality, distant at least 1000 meters from each other. The plots were 250 m long, of variable width, and followed topographic contour. Linear regression models were used to evaluate the effects of altitude, slope, light incidence and food availability on indices of abundance (average number of records/plot) or occurrence (number of plots which the species was found) for Ameiva ameiva (Teidae), Coleodactylus septentrionalis, Gonatodes humeralis (Gekkonidae), Leposoma percarinatum (Gymnophthalmidae) e Plica umbra (Tropiduridae). Calibration models were generated in one of the areas and evaluated in the other to assess their predictive efficiency. The models explained little of the variability in the indices of abundance or occurrence of the lizard species and the models of one area were not able to predict the abundance or occurrence of the species in the other area. However, there was little evidence that the predictor variables had different relationships with P. umbra and G. humeralis in each area. Although the little influence of the environmental variables on most species at both study areas, suggesting that species are generalists, three species were significantly influenced by at least one variable. It s possible that larger environmental and geographic scale studies can be a good alternative to predictive models.